[en] In this paper it is shown that orthogonal deviation increases the ranging error of navigation signals, and a method for the estimation of orthogonal and phase deviation of the I and Q components of a constant-envelope signal is proposed. A measurement process is introduced and the measurement accuracy for different signal-to-noise ratios and data lengths is provided. Moreover, in the process of evaluation, a very important conclusion is made: when a digital signal is filtered, the filter bandwidth does not affect measurement accuracy. The corresponding proof is given. The accuracy of the proposed method and measurement is verified by simulations. In simulations, an expectation-maximum (EM) algorithm was used to estimate the constellation coordinates, and the shortcomings of the EM algorithm in high-precision parameter estimation were determined and the corresponding corrections made. Finally, the proposed method was used to estimate both orthogonal deviation and phase deviation of a real satellite signal. (paper)